This invention relates to steering mechanisms for vehicles and particularly to steering mechanisms of aquatic crafts.
Steering mechanisms are generally available for boats employing outboard motors. These mechanisms are equipped with a hydraulic motor connected to the tiller arm of the outboard motor and are actuated by a valve or pump which is coupled with the steering wheel. Such mechanisms are generally available in two forms, each employing a hydraulic motor with double acting cylinder henceforth referred to as a double acting motor. In one prior art system, the cylinder is mounted to the tiller arm with the piston being coupled through a linkage to the mounting bracket. In another system, the piston is fixed relative to the tiller arm while the cylinder is coupled via a linkage to the mounting bracket.
Steering is achieved by supplying fluid under pressure to the appropriate side of the piston which induces rotation of the outboard motor about its steering axis relative to a mounting bracket. Rotation of the outboard motor also causes the double acting motor to rotate relative to the mounting bracket and thus has several shortcomings.
Firstly, all hoses and couplings providing fluid under pressure to the cylinder must move with the double acting motor thereby increasing wear and consequently reducing operating life. Rotation of the double acting motor can also cause inadvertent contact with an unattentive occupant or with objects such as paddles and skis thereby causing personal injury or damage to the mechanism. This problem is compounded as the use of a double acting motor requires the use of a piston which passes through each end of the cylinder and projects laterally across the stern. The use of a double acting motor requires a seal at each end of the cylinder and a seal between the piston and cylinder wall to define the inner chambers. Because the ends of the piston are offset from the tiller arm, a linkage is required at one or both ends of the piston. Consequently, the normal forces required to turn the outboard motor often result in large bending moments in the piston which are reacted at the seals thereby reducing their operating life.